In recent years, a scanning tunneling microscope (STM), with which the surface states of materials are directly observed at atomic level, has been developed. Also, an atomic force microscope (AFM) and a magnetic force microscope (MFM) have been developed using the principle of STM. With these microscopes, a sharp-pointed probe and the surface of material are positioned close to each other so as to detect a tunnel current flowing between them, and an atomic force and a magnetic force working between them. A photon STM, which causes light to fall on a sample surface using a sharp-pointed optical probe and detects evanescent light overflown from the sample surface, is developed by using the principle of STM.
Various apparatuses for recording and reproducing information at atomic level by using the principle of STM are proposed. Another proposed apparatus focuses light into a size not larger than the diffraction limit using the principle of the photon STM, records information with the focused light and reproduces the information by detecting reflected light, transmitted light, or evanescent light from a substance recorded (for example, see Applied Physics, Letter 61(2), 13 Jul. 1992, page 142).
FIG. 27 illustrates a recording and reproduction apparatus using an optical probe.
An optical probe 803 is formed at an end of an optical fiber 800. The optical fiber 800 is fixed to a movable supporting section 822. The supporting section 822 is moved by a driving section 821. The driving section 821 and a recording medium 810 are fixed on a base 820. The optical probe 803 is moved to a desired location on the recording medium 810 by driving the supporting section 822 by the driving section 821.
The recording medium 810 is constructed by a transparent substrate 811, and a recording layer 812 formed on the transparent substrate 811. The optical probe 803 is positioned so that its tip is located close to the recording layer 812.
When recording information, light whose intensity has been modulated according to the information is directed to the optical fiber 800, and focused into a size which is not larger than the diffraction limit by the optical probe 803. Thus, high-density recording of information on the recording layer 812 is achieved.
A method of manufacturing the optical probe 803 is illustrated in FIGS. 28(a) to 28(c).
As illustrated in FIG. 28(a), the optical fiber 800 is heated until part thereof is fused. In this state, the optical fiber 800 are pulled in the right and left directions as shown in FIG. 28(b). Then, a red heated section 801 of the optical fiber 800 is split as shown in FIG. 28(c), thereby producing the sharp-pointed optical probe 803.
With a conventional structure, however, it is difficult to make the tip of the optical probe 803 having a uniform diameter. Hence, the conventional structure does not allow mass-production of the standardized optical probe 803.
Moreover, with the conventional structure, when recording and reproducing a plurality of pieces of information simultaneously using a bundle of optical probes 803, the distance between each of the optical probes 803 and the recording medium 810 can hardly be kept uniform.